1. The Field of the Invention
The present invention relates to a guide for a sliding door, in particular of a vehicle. Furthermore, the present invention relates to a related method for manufacturing a guide for a sliding door, in particular of a vehicle.
2. The Relevant Technology
At the state of the art, it is known a guide for a sliding door, in particular of a vehicle, comprising a first straight section, a curved section and a second straight section, said curved section being located between the first and the second straight section.
As it is known, the first and the second straight section of the guide are of a variable length (usually depending on the type of vehicle) and allow the sliding of the door relative to the vehicle associated thereto, while the curved section of the guide allows the door to come out from the shape or contour of the vehicle.
Furthermore, such a guide of the known type is realized in such a way that it comprises a first portion having a substantially inverted U-shaped cross-section and comprising a first side wall, an intermediate wall and a second side wall facing said first side wall.
Said first guide portion is adapted to receive at least one first rolling element associated with the door of said vehicle, said first rolling element being guided by the first and second side wall of said first portion in order to accompany the door while passing from a closing condition to an open condition, and vice versa.
Usually, said at least one first rolling element is constituted by a wheel, which is associated to the first portion of the guide in such a way as to have a first rotation axis substantially vertical.
The guides known in the art are then usually made in such a way as to include a second substantially L-shaped portion and provided with a first strip coupled to the first side wall of the first portion and a second substantially horizontal strip facing the intermediate wall of the first portion.
In such an embodiment, said second strip constitutes a substantially horizontal support surface for at least one second rolling element associated with the door of said vehicle, so as to hold the door of the vehicle while passing from the closed condition to the open position, and vice versa.
Usually, also said at least one second rolling element is constituted by at least one wheel, which is associated to the second portion of the guide in such a way as to have a substantially horizontal rotation axis (i.e., a rotation axis substantially parallel to the second strip of the second portion, facing the intermediate wall of the first portion).
However, the above described guide has drawbacks.
Since the curved section of the sliding guide is usually realized by an apparatus for bending and stretching profiles (said apparatuses being generally known as “stretch and bending” apparatuses), the sliding guide is made such as to have a certain clearance between the rolling element and the first portion of the guide, in particular in correspondence of said first and second straight section of the guide.
In fact, during the stretch and bending operations of the profile, in said curved section of the sliding guide the material tends to stretch and draw more material toward the outside of the curved section, causing a decrease of the distance between the first and the second side wall of the substantially U-formed first section.
Consequently, in the guides known at the state of the art, the clearance compared to the first rolling element that the first portion of the guide has in correspondence of the rectilinear sections is necessary in order to achieve a curved section in which the distance between the first and the second side wall of said first section is sufficiently large to allow the passage of said first rolling element associated with a door, in particular of a vehicle.
Thus, it is apparent that the guides known in the art are made, in particular in correspondence of the rectilinear sections, in such a way to have a clearance that does not allow to accurately and precisely guide the rolling element associated with the door.
Furthermore, it is obvious that such a clearance would cause undesired noise during the passage of the door from a closed condition to an open condition, and vice versa; in addition, this clearance does not allow an optimal operation of the system.
Some documents of the prior art are intended to solve the above drawbacks by different solutions.
For example, in order to compensate the clearance between the rolling elements and the guide, document WO2005028794A1 discloses the use of a trolley comprising a pair of rollers fixed on opposite sides of a rod for guiding the door during its opening and closing movements, said rod being pivoted to the guide and being associated with an elastic element adapted to maintain the contact of each wheel with the guide walls.
However, this solution has some drawbacks, since it is affected by the weight of the door and by the wear that determine a malfunction of the elastic element and of the other components of the system, in particular during the time. As a result, document WO2005028794A1 does not allow to find a solution that will be effective and durable.
Also document DE102008021802A1 aims to provide a solution to the problems resulting from the implementation of a clearance in the guide rail.
In particular, said document provides for the realization of said sliding guide in a substantially U-shaped first portion and a L-shaped second portion separated therebetween, so as to carry them out with a reduced tolerance of production and combine them later, for example during their attachment to the vehicle.
However, also this solution has some drawbacks, since it appears to be excessively complex and requires times and costs of realization and assembly really excessive.